+/** HACK, A value from another process
+ *
+ * This represents a value from another process:
+ *
+ * * constructor/destructor are disabled;
+ *
+ * * raw memory copy (std::memcpy) is used to copy Remote<T>;
+ *
+ * * raw memory comparison is used to compare them;
+ *
+ * * when T is a trivial type, Remote is convertible to a T.
+ *
+ * We currently only handle the case where the type has the same layout
+ * in the current process and in the target process: we don't handle
+ * cross-architecture (such as 32-bit/64-bit access).
+ */
+template<class T>
+union Remote {
+private:
+ T buffer;
+public:
+ Remote() {}
+ ~Remote() {}
+ Remote(T& p)
+ {
+ std::memcpy(&buffer, &p, sizeof(buffer));
+ }
+ Remote(Remote const& that)
+ {
+ std::memcpy(&buffer, &that.buffer, sizeof(buffer));
+ }
+ Remote& operator=(Remote const& that)
+ {
+ std::memcpy(&buffer, &that.buffer, sizeof(buffer));
+ return *this;
+ }
+ T* getBuffer() { return &buffer; }
+ const T* getBuffer() const { return &buffer; }
+ std::size_t getBufferSize() const { return sizeof(T); }
+ operator T() const {
+ static_assert(std::is_trivial<T>::value, "Cannot convert non trivial type");
+ return buffer;
+ }
+ void clear()
+ {
+ std::memset(static_cast<void*>(&buffer), 0, sizeof(T));
+ }
+
+};
+